The insulation of masonry building blocks has taken a variety of forms. After a wall has been constructed or partially constructed of such blocks, insulation has been introduced in situ. Insulation has also been molded directly in the cavities of such blocks. Further, various special types of blocks have been provided with insulation mounted internally or secured externally. One form of block insulation, rapidly gaining in popularity, is disclosed in U.S. Pat. No. 3,885,363 to Richard W. Whittey entitled INSULATED BLOCK. As disclosed therein, preformed insulating inserts are introduced to the cavities of building blocks at the block plant after the blocks have been formed and the blocks may thereafter be handled during construction in the ordinary manner of uninsulated blocks. Obvious advantages in efficiency and convenience are thus achieved.
In the last mentioned insulating technique, however, as in substantially all of the methods employed, the building blocks have two or more transverse webs between inner and outer side sections and substantial heat transfer occurs conductively therethrough. To date, there has been no effective solution to this problem.